The present invention relates to seals, and particularly to a seal for a pipe extending through a wall.
Various seal assemblies can be used to seal the annular space between a pipe and a wall through which it extends. For example, Hauff, U.S. Pat. No. 4,993,724 teaches a circular elastic one-piece sealing structure having a split that can be deformed opposite to the split so that the structure can be spread to fit around the conduit. Similarly, Israelson, U.S. Pat. No. 5,548,934, is directed to a firestop that contains a one-piece seal which allows longitudinal and radial movement of a pipe located in a partition wall.
A multi-segmented seal assembly is also well-known in the art. For example, Thunderline Corporation (Belleville, Mich.) manufactures an annular seal assembly comprised of a number of segmented seal blocks connected by bolts to form a ring structure. Pressure plates are located on each face of the seal blocks. When the assembly is placed around a pipe in an annular space, the bolts are tightened, thereby compressing the seal blocks so that a seal is formed tightly engaging both the wall and the pipe. See Griffiths, U.S. Pat. No. 5,340,123; Griffiths, U.S. Pat. No. 5,213,341; Gignac, U.S. Pat. No. 3,703,297; Barton, U.S. Pat. No. 3,649,034; and Barton U.S. Pat. No. 3,528,668. Another multi-segmented seal assembly has been manufactured by the Metraflex Company (the assignee of the present invention) under the trademark METRASEAL(copyright).
Conventional seal assemblies generally have an elastomeric material directly in contact with the pipe. As a result, when the pipe is pushed through the seal, the seal may become dislodged from the wall.
The present invention is directed to an improvement to such conventional seal assemblies. The present invention involves a seal assembly having a friction-reducing layer, such as wire mesh, in contact with the pipe. Because the coefficient of friction between the pipe and the seal assembly is decreased by the addition of the wire mesh, the seal is not dislodged from the wall when the pipe is pushed through the seal assembly.
The present invention is directed to an annular seal assembly comprised of a plurality of interlocking seal blocks connected to a plurality of pressure plates by a plurality of bolts to form a seal belt. The inner surface of the seal belt contains a friction-reducing layer, such as a wire mesh.